/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.search.function;

import org.apache.lucene.search.*;
import org.apache.lucene.index.IndexReader;

/**
 * Represents field values as different types. Normally created via a
 * {@link ValueSource} for a particular field and reader.
 * 
 * @version $Id: DocValues.java 1140724 2011-06-28 17:00:20Z yonik $
 */

// DocValues is distinct from ValueSource because
// there needs to be an object created at query evaluation time that
// is not referenced by the query itself because:
// - Query objects should be MT safe
// - For caching, Query objects are often used as keys... you don't
// want the Query carrying around big objects
public abstract class DocValues {

	public byte byteVal(int doc) {
		throw new UnsupportedOperationException();
	}

	public short shortVal(int doc) {
		throw new UnsupportedOperationException();
	}

	public float floatVal(int doc) {
		throw new UnsupportedOperationException();
	}

	public int intVal(int doc) {
		throw new UnsupportedOperationException();
	}

	public long longVal(int doc) {
		throw new UnsupportedOperationException();
	}

	public double doubleVal(int doc) {
		throw new UnsupportedOperationException();
	}

	public String strVal(int doc) {
		throw new UnsupportedOperationException();
	}

	public abstract String toString(int doc);

	// For Functions that can work with multiple values from the same document.
	// This does not apply to all functions
	public void byteVal(int doc, byte[] vals) {
		throw new UnsupportedOperationException();
	}

	public void shortVal(int doc, short[] vals) {
		throw new UnsupportedOperationException();
	}

	public void floatVal(int doc, float[] vals) {
		throw new UnsupportedOperationException();
	}

	public void intVal(int doc, int[] vals) {
		throw new UnsupportedOperationException();
	}

	public void longVal(int doc, long[] vals) {
		throw new UnsupportedOperationException();
	}

	public void doubleVal(int doc, double[] vals) {
		throw new UnsupportedOperationException();
	}

	public void strVal(int doc, String[] vals) {
		throw new UnsupportedOperationException();
	}

	public Explanation explain(int doc) {
		return new Explanation(floatVal(doc), toString(doc));
	}

	public ValueSourceScorer getScorer(IndexReader reader) {
		return new ValueSourceScorer(reader, this);
	}

	// A RangeValueSource can't easily be a ValueSource that takes another
	// ValueSource
	// because it needs different behavior depending on the type of fields.
	// There is also
	// a setup cost - parsing and normalizing params, and doing a binary search
	// on the StringIndex.
	// TODO: change "reader" to AtomicReaderContext
	public ValueSourceScorer getRangeScorer(IndexReader reader,
			String lowerVal, String upperVal, boolean includeLower,
			boolean includeUpper) {
		float lower;
		float upper;

		if (lowerVal == null) {
			lower = Float.NEGATIVE_INFINITY;
		} else {
			lower = Float.parseFloat(lowerVal);
		}
		if (upperVal == null) {
			upper = Float.POSITIVE_INFINITY;
		} else {
			upper = Float.parseFloat(upperVal);
		}

		final float l = lower;
		final float u = upper;

		if (includeLower && includeUpper) {
			return new ValueSourceScorer(reader, this) {
				@Override
				public boolean matchesValue(int doc) {
					float docVal = floatVal(doc);
					return docVal >= l && docVal <= u;
				}
			};
		} else if (includeLower && !includeUpper) {
			return new ValueSourceScorer(reader, this) {
				@Override
				public boolean matchesValue(int doc) {
					float docVal = floatVal(doc);
					return docVal >= l && docVal < u;
				}
			};
		} else if (!includeLower && includeUpper) {
			return new ValueSourceScorer(reader, this) {
				@Override
				public boolean matchesValue(int doc) {
					float docVal = floatVal(doc);
					return docVal > l && docVal <= u;
				}
			};
		} else {
			return new ValueSourceScorer(reader, this) {
				@Override
				public boolean matchesValue(int doc) {
					float docVal = floatVal(doc);
					return docVal > l && docVal < u;
				}
			};
		}
	}
}
